Collateral ligament reconstruction of the knee: when it is needed and what to expect

The knee has four main ligaments. The two collateral ligaments sit on either side of the joint: the medial collateral ligament (MCL) on the inner side and the lateral collateral ligament (LCL) on the outer side. The Whittington Health patient information describes the MCL as limiting inward movement of the knee and the LCL as limiting outward movement.

Royal Cornwall Hospitals explains that soft tissue knee injuries are graded by severity. In grade 1, a few fibres are damaged or torn and will usually heal naturally; this is often called a sprain. In grade 2, more fibres are torn but the ligament is still intact, referred to as a severe sprain. In grade 3 the ligament is completely disrupted, the knee joint is unstable and an operation may be needed.

The Royal Cornwall pages say that for LCL injuries grade 1 and 2 injuries usually heal well, while some grade 2 and 3 injuries need an operation, which may happen in the first few weeks after the injury or later depending on individual circumstances. For MCL injuries it says the ligament may heal on its own over time, or you may need an operation, and that your individual circumstances guide whether it recommends reconstructing the MCL.

If surgery is an option, a knee surgeon will discuss the risks and benefits so that you can make an informed decision. The Whittington Health information says ligament reconstruction surgery is recommended for severe injuries, especially ACL tears, using grafts from the patient's own tissue or a donor, and that repair may be performed for partial tears, particularly of the PCL and MCL. NHS Borders referral guidance lists associated ACL or meniscal injuries among the reasons a confirmed MCL injury should be referred, because they affect the plan.

For a recent injury Royal Cornwall advises, in the first 72 hours, protecting the knee, resting, applying a cold pack regularly, compression, elevating the leg above hip level and using crutches or a support bandage. It describes ice packs wrapped in a thin wet towel for up to 15 minutes every few hours, not placed directly on the skin, and suggests taking pain relief as instructed. You may be sent for an MRI scan, X-ray or other imaging if a more severe injury is suspected, and a specialist physiotherapist may follow up.

The Royal Cornwall care plans describe bracing and exercise rather than a single timetable. For suspected LCL injury it says the brace must be worn for exercises for at least 6 weeks, and for suspected MCL injury that you need to wear the brace for 6 to 12 weeks depending on the severity of the injury. Both pages advise no sport at all for at least 6 weeks and avoiding impact sports, jumping, running, dancing and heavy lifting for at least 12 weeks. They also describe maturation of the scar from 6 weeks up to a year.

Physiotherapy aims to manage pain, minimise swelling, maintain range of movement and keep the front thigh muscles working so that the hamstrings do not take over. If you need an operation, the trust says prehabilitation exercises help you prepare and recover. Your consultant may give a different, personalised plan, and operation-specific protocols vary between surgeons, so follow the one you are given.

The Whittington Health information says mild sprains can heal within a few weeks with proper care, while severe ligament tears may require months of rehabilitation or surgical intervention. Your surgeon and physiotherapist will advise when it is safe to return to sport, which depends on strength and stability rather than a fixed date. Smoking can slow healing, and Royal Cornwall advises stopping smoking during the healing phase, eating well and staying active as far as the plan allows.

See a GP, minor injuries unit or emergency department if you have injured your knee and cannot put weight on it, it gives way, it is very swollen, or the foot is numb, cold or discoloured. After surgery, contact your surgical team for increasing pain or swelling, redness or discharge from the wound, a high temperature or a hot, swollen, painful calf. Royal Cornwall points to its surgery information for how to care for stitches and the signs of infection.

Knee ligament injuries are usually assessed in minor injuries units, emergency departments and fracture clinics, with referral to orthopaedic knee surgeons and physiotherapy. Private MRI and consultations are also available, and reconstructive surgery can be done privately. In either case, a clear plan for bracing and physiotherapy matters as much as the operation itself.